The present invention relates to a copper tetragonal age-hardened-zinc-nickel-manganese alloy. 2. Prior Art
Nickel silver (known as Neusilber in German, maillschort blanc argent in French, and alpacca or alpaca in Italian and Spanish) is understood to mean a Ni-Cu-Zn-alloy, which has a silver-like colour, good corrosion resistance and good strength properties, and which is used as a construction or manufacturing material in mechanical engineering, electrical engineering, architecture as well as for the manufacture of jewelry and articles of craftsmanship.
Known nickel silver alloys may, for example, contain:
45-70%, preferably 60-64%, Cu (for example 62%) PA1 8-45%, preferably 15-24%, Zn (for example 20%) and PA1 8-28%, preferably 12-25%, Ni (for example 18%). PA1 1-15%, preferably 2-6%, Mn (for example 4%). PA1 36 to 44% copper, PA1 21 to 28% in toto of zinc with or without tin and/or indium, provided that tin and/or indium if present amount together to at most 10%, PA1 18 to 25% in toto of nickel with or without cobalt, provided that cobalt if present amounts to at most 5%, PA1 10 to 18% manganese, PA1 Up to 0.5% of at least one of beryllium and the rare-earth metals, provided that neither the beryllium content nor the rare-earth metals content exceeds 0.3%, additives from the group lithium, magnesium, calcium and titanium, serving as de-oxidising elements, and iron as the usual impurity. The balance, if any, of the alloy may comprise usual commercial impurities.
Nickel silver alloys having an Mn additive are also known. They also contain, for example:
In general, these known nickel silver alloys are in general not capable of being hardened by heat treatment, but are cold-formed in order to obtain an increase in strength, since the ductility is considerably reduced. They do indeed have a white color, but this tends towards being yellowish.